Objective: The aim of this study was to investigate the competitive adsorption of human albumin (Alb), human fibrinogen (Fib) and human immunoglobulin G (IgG) on surface of biomaterial based on the special molecular recognition and interaction between antigen and antibody with a biomedical sensor Reflectometry Interference Spectroscopy (RIfS). Materials and Methods: The RIfS setup used has been developed in our laboratory (1). The materials to be tested were polyurethane (PU) and polystyrene (PS). The thin films of PU/PS were prepared using a spin-coating method. The thickness of the films was ~650 nm. Three kinds of proteins, Alb, Fib and IgG (Sigma Mo) were used as antigen and three kinds antibody used were sheep anti-human Alb, sheep anti-human Fib and rabbit anti-human IgG. 1. Investigation of interaction between three kinds of proteins alone with special antibodies: At first, the protein adsorption process has been performed as reported in (2). Then, bovine serum albumin (BSA) was added to fill in the areas of the material surface which were not covered by proteins and the PBS flowed over the surface of the PU/PS film to make cleaning. After such a treatment the special antibody solution flowed into the adsorption cell and the kinetic interaction process of antibody with proteins on the surface of the PU/PS film were oberseved in situ on the monitor of a computer. Until the kinitic adsorption curve of antibodies become stable, the PBS was driven into the adsorption cell again to wash off the antibodies which did not firmly adsorpted on the material surface. The wash process would get a response on the adsorption curve. For each kind of proteins, at least three tests were performed. 2. Performance of protein competitive adsorption: At first the protein adsorption process was performed with a mixture of three kinds of proteins (Aib:Fig:IgG=1:1:1). After mixed proteins were competitive adsorbed onto the surface of the PU/PS film, different antibodies were added to measure the interaction between the specific antibodys with each protein in mixed proteins layer adsorbed on the PU/PS film. 3. Caculation of the quantity of each protein in mixed protein layer that competitive adsorbed on the PU/PS: According to the results from 1 and 2, the percent of one kind of proteins in mixed protein layer competitive adsorbed on the surface of the material (Ppx ) was calculated with followed formula: Ppx=(Tp

The quantity and secondary structure of adsorbed albumin (Alb) and immunoglobulin G (IgG) on two kinds of biomaterial surfaces-polyurethane (PU (H50-50)) and polystyrene (PS) were studied using Fourier transform infrared spectroscopy (FTIR). The original spectra tested by FTIR were processed using second-derivation and self-deconvolution techniques to obtain the content of different secondary structures of adsorbed proteins, which could be used to evaluate the denatured degree of proteins. Results showed that the quantity of Alb adsorbed on PU (H50-50) surface is larger than PS. The hydrophobic features of material played a role in conformational change of adsorbed protein, and indicated that the denatured degree caused by hydrophobic PS was greater than hydrophilic PU (H50-50). The blood compatibility of PU (H50-50) was likely to be better than PS.

The aim of this study was to compare the plasma protein adsorptive property of the natural hydroxyapatite (HA) and the synthesized HA to human albumin (Alb), fibrinogen (Fib) and immunoglobulin G (IgG). Different methods such as reflectometry interference spectroscopy (RIfS) measuring, Fourier transform infrared spectroscopy (FTIR) analysis and weighing assessment were used to measure the adsorbed amount of Alb, Fib and IgG on the natural HA and the synthesized HA. To compare the adsorptive property of protein adsorbed on these two kinds of materials, the ratio of Alb/Fib (RA/F) and the ratio of Alb/IgG (RA/I) were calculated. The results from all three methods showed that the values of RA/F and RA/I obtained with natural HA were smaller than those obtained with synthesized HA, that indicated that the natural HA adsorbed more human fibrinogen than human albumin and thas it would enhance blood coagulation and in favor of bone repairing.

The state-of-art of the pick-up, the process and the regeneration of central neural signals by means of microelectronic techniques are reviewed. The in-detail discussed topics include the electrodes for neural signal pick-up and for the function electrical stimulation (FES) of neurons, the integrated circuits (IC) for the neural signal process and for the FES-signal generation, the energy supply and the low-power design of the ICs, as well as the biocompatibility test and the micro operation of the whole system implanted in-body.

To prepare natural nano-HA and a natural nano-hydroxypatite/chitosan (CH) composite and to study the biocompatibility of natural nano-hydroxypatite/chitosan composite. Natural hydroxyapatite (HA) was prepared from animal’s bone according to a calcining method, the natural nano-HA was prepared by using planetary ball milling, and the composite was prepared via in-situ precipitation. TEM and SEM were used to observe the size of natural nao-hydroxypatite and the microstructure of the composite. The biocompatibility of natural nano-HA/CH composite was evaluated by MTT test. The TEM micrography of the natural nano-HA showed that the size of the particles is below 100nm, and the composite reported in this study has layer-by-layer structure. The result of MTT-test showed the cytotoxicity level of the prepared composite was 0. The nano-HA/CH composite has good biocompatibility, and it can be potentially applied as internal fixation of bone fracture.